ppapi: VideoEncoder: augment precision of the IVF container

ppapi: VideoEncoder: augment precision of the IVF container

Use millisecond timestamps in the IVF container rather than having
1.0/30 units of time. This prevents a drift in the replay of the
video because the recorder might not schedule frames at exactly
33.3333ms.

BUG=503153
TEST=record a 2 minutes vp8 video using the video encoder NaCl SDK and verify the produced video last exactly 2 minutes

Committed: https://crrev.com/0141e7812a6a7b6b24b7b4df25bf5d4a1bc8c348
Cr-Commit-Position: refs/heads/master@{#338694}

[llandwerlin-old, 2015-07-10 16:39:21]

lionel.g.landwerlin@intel.com changed reviewers:
+ bbudge@chromium.org, binji@chromium.org

[llandwerlin-old, 2015-07-10 16:39:21]

bbudge@, binji@: Could you review this change? This is the same change in the 2
different files. Thanks.

[bbudge, 2015-07-10 16:58:21]

lgtm

[binji, 2015-07-14 15:45:34]

lgtm

[llandwerlin-old, 2015-07-14 15:48:02]

The CQ bit was checked by lionel.g.landwerlin@intel.com

[commit-bot: I haz the power, 2015-07-14 15:48:36]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1226203010/1

[commit-bot: I haz the power, 2015-07-14 15:48:39]

The author lionel.g.landwerlin@intel.com has not signed Google Contributor
License Agreement. Please visit https://cla.developers.google.com to sign and
manage CLA.

[commit-bot: I haz the power, 2015-07-14 15:57:41]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-14 15:58:31]

Patchset 1 (id:??) landed as
https://crrev.com/0141e7812a6a7b6b24b7b4df25bf5d4a1bc8c348
Cr-Commit-Position: refs/heads/master@{#338694}